An important point for further work is to extend the current setup
from the base category \(\mathbf {Set} \)  to algebraic categories (such as join
semi-lattices or positive convex algebras) in order to generalize our
results to expression calculi involving convenient additional
operations (reflecting the ambient algebraic theory) such as
addition. A closely related point is the connection with coalgebraic
determinization [1]}; it should be interesting to see
whether our ideas can lead to expression calculi for coarser system
equivalences than bisimilarity, such as trace equivalence for
transition systems or distribution bisilimarity for Segala systems.
Such a generalization might be based on our recent approach
to coalgebraic trace semantics via graded monads [2]}.
